L-Glutamin / glutamin peptid

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Effect of glutamine supplementation combined with resistance training in young adults.

Candow DG, Chilibeck PD, Burke DG, Davison KS, Smith-Palmer T.

College of Kinesiology, University of Saskatchewan, Saskatoon, Canada.

The purpose of this study was to assess the effect of oral glutamine supplementation combined with resistance training in young adults. A group of 31 subjects, aged 18-24 years, were randomly allocated to groups (double blind) to receive either glutamine (0.9 g x kg lean tissue mass(-1) x day(-1); n = 17) or a placebo (0.9 g maltodextrin x kg lean tissue mass(-1) x day(-1); n = 14 during 6 weeks of total body resistance training. Exercises were performed for four to five sets of 6-12 repetitions at intensities ranging from 60% to 90% 1 repetition maximum (1 RM). Before and after training, measurements were taken of 1 RM squat and bench press strength, peak knee extension torque (using an isokinetic dynamometer), lean tissue mass (dual energy X-ray absorptiometry) and muscle protein degradation (urinary 3-methylhistidine by high performance liquid chromatography). Repeated measures ANOVA showed that strength, torque, lean tissue mass and 3-methylhistidine increased with training (P < 0.05), with no significant difference between groups. Both groups increased their 1 RM squat by approximately 30% and 1 RM bench press by approximately 14%. The glutamine group showed increases of 6% for knee extension torque, 2% for lean tissue mass and 41% for urinary levels of 3-methylhistidine. The placebo group increased knee extension torque by 5%, lean tissue mass by 1.7% and 3-methylhistidine by 56%. We conclude that glutamine supplementation during resistance training has no significant effect on muscle performance, body composition or muscle protein degradation in young healthy adults.

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Boza JJ, Dangin M, Moennoz D, Montigon F, Vuichoud J, Jarret A, Pouteau E, Gremaud G, Oguey-Araymon S, Courtois D, Woupeyi A, Finot PA, Ballevre O.

Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers
Nestle Research Center, Vers-Chez-Les-Blanc, 1000 Lausanne 26, Switzerland.

The objectives of the present study were to determine the splanchnic extraction of glutamine after ingestion of glutamine-rich protein ((15)N-labeled oat proteins) and to compare it with that of free glutamine and to determine de novo glutamine synthesis before and after glutamine consumption. Eight healthy adults were infused intravenously in the postabsorptive state with L-[1-(13)C]glutamine (3 micromol x kg(-1) x h(-1)) and L-[1-(13)C]lysine (1.5 micromol x kg(-1) x h(-1)) for 8 h. Four hours after the beginning of the infusion, subjects consumed (every 20 min) a liquid formula providing either 2.5 g of protein from (15)N-labeled oat proteins or a mixture of free amino acids that mimicked the oat-amino acid profile and contained L-[2,5-(15)N(2)]glutamine and L-[2-(15)N]lysine. Splanchnic extraction of glutamine reached 62.5 +/- 5.0% and 66.7 +/- 3.9% after administration of (15)N-labeled oat proteins and the mixture of free amino acids, respectively. Lysine splanchnic extraction was also not different (40.9 +/- 11.9% and 34.9 +/- 10.6% for (15)N-labeled oat proteins and free amino acids, respectively). The main conclusion of the present study is that glutamine is equally bioavailable when given enterally as a free amino acid and when protein bound. Therefore, and taking into consideration the drawbacks of free glutamine supplementation of ready-to-use formulas for enteral nutrition, protein sources naturally rich in this amino acid are the best option for providing stable glutamine.

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Int J Sports Med 2000 Jan;21(1):25-30 Related Articles, Links


The effect of free glutamine and peptide ingestion on the rate of muscle glycogen resynthesis in man.

van Hall G, Saris WH, van de Schoor PA, Wagenmakers AJ.

Department of Human Biology, Maastricht University, The Netherlands. RH01769@RH.DK

The present study investigated previous claims that ingestion of glutamine and of protein-carbohydrate mixtures may increase the rate of glycogen resynthesis following intense exercise. Eight trained subjects were studied during 3 h of recovery while consuming one of four drinks in random order. Drinks were ingested in three 500 ml boluses, immediately after exercise and then after 1 and 2 h of recovery. Each bolus of the control drink contained 0.8 g x kg(-1) body weight of glucose. The other drinks contained the same amount of glucose and 0.3 g x kg(-1) body weight of 1) glutamine, 2) a wheat hydrolysate (26% glutamine) and 3) a whey hydrolysate (6.6% glutamine). Plasma glutamine, decreased by approximately 20% during recovery with ingestion of the control drink, no changes with ingestion of the protein hydrolysates drinks, and a 2-fold increase with ingestion of the free glutamine drinks. The rate of glycogen resynthesis was not significantly different in the four tests: 28 +/- 5, 26 +/- 6, 33 +/- 4, and 34 +/- 3 mmol glucosyl units x kg(-1) dry weight muscle x h(-1) for the control, glutamine, wheat- and whey hydrolysate ingestion, respectively. It is concluded that ingestion of a glutamine/carbohydrate mixture does not increase the rate of glycogen resynthesis in muscle. Glycogen resynthesis rates were higher, although not statistically significant, after ingestion of the drink containing the wheat (21 +/- 8%) and whey protein hydrolysate (20 +/- 6%) compared to ingestion of the control and free glutamine drinks, implying that further research is needed on the potential protein effect.

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Metabolism 2000 Dec;49(12):1555-60 Related Articles, Links


Intravenous glutamine does not stimulate mixed muscle protein synthesis in healthy young men and women.

Zachwieja JJ, Witt TL, Yarasheski KE.

Exercise and Nutrition Program, Pennington Biomedical Research Center, Baton Rouge, LA, USA.

We investigated the effects of a glutamine-supplemented amino acid mixture on vastus lateralis muscle protein synthesis rate in healthy young men and women. Three men and 3 women (27.8 +/- 2.0 yr, 22.2 +/- 1.0 body mass index [BMI], 56.1 +/- 4.5 kg lean body mass [LBM]) received a 14-hour primed, constant intravenous infusion of L[1-13C]leucine to evaluate the fractional rate of mixed muscle protein synthesis. In addition to tracer administration, a clinically relevant amino acid mixture supplemented with either glutamine or glycine in amounts isonitrogenous to glutamine, was infused. Amino acid mixtures were infused on separate occasions in random order at a rate of 0.04 g/kg/h (glutamine at approximately 0.01 g/kg/h) with at least 2 weeks between treatment. For 2 days before and on the day of an infusion, dietary intake was controlled so that each subject received 1.5 g protein/kg/d. Compared with our previous report in the postabsorptive state, amino acid infusion increased the fractional rate of mixed muscle protein synthesis by 48% (P < .05); however, the addition of glutamine to the amino acid mixture did not further elevate muscle protein synthesis rate (ie, 0.071% +/- 0.008%/h for amino acids + glutamine v 0.060% +/- 0.008%/h for amino acids + glycine; P = .316). Plasma glutamine concentrations were higher (P < .05) during the glutamine-supplemented infusion, but free intramuscular glutamine levels were not increased (P = .363). Both plasma and free intramuscular glycine levels were increased when extra glycine was included in the infused amino acid mixture (both P < .0001). We conclude that intravenous infusion of amino acids increases the fractional rate of mixed muscle protein synthesis, but addition of glutamine to the amino acid mixture does not further stimulate muscle protein synthesis rate in healthy young men and women.

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J Appl Physiol 2002 Sep;93(3):813-22 Related Articles, Links


Exercise-induced immunodepression- plasma glutamine is not the link.

Hiscock N, Pedersen BK.

Copenhagen Muscle Research Centre and Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark.

The amino acid glutamine is known to be important for the function of some immune cells in vitro. It has been proposed that the decrease in plasma glutamine concentration in relation to catabolic conditions, including prolonged, exhaustive exercise, results in a lack of glutamine for these cells and may be responsible for the transient immunodepression commonly observed after acute, exhaustive exercise. It has been unclear, however, whether the magnitude of the observed decrease in plasma glutamine concentration would be great enough to compromise the function of immune cells. In fact, intracellular glutamine concentration may not be compromised when plasma levels are decreased postexercise. In addition, a number of recent intervention studies with glutamine feeding demonstrate that, although the plasma concentration of glutamine is kept constant during and after acute, strenuous exercise, glutamine supplementation does not abolish the postexercise decrease in in vitro cellular immunity, including low lymphocyte number, impaired lymphocyte proliferation, impaired natural killer and lymphokine-activated killer cell activity, as well as low production rate and concentration of salivary IgA. It is concluded that, although the glutamine hypothesis may explain immunodepression related to other stressful conditions such as trauma and burn, plasma glutamine concentration is not likely to play a mechanistic role in exercise-induced immunodepression

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Effect of glutamine and protein supplementation on exercise-induced decreases in salivary IgA.

Krzywkowski K, Petersen EW, Ostrowski K, Link-Amster H, Boza J, Halkjaer-Kristensen J, Pedersen BK.

The Copenhagen Muscle Research Centre, Rigshospitalet, 2200 Copenhagen, Denmark.

Postexercise immune impairment has been linked to exercise-induced decrease in plasma glutamine concentration. This study examined the possibility of abolishing the exercise-induced decrease in salivary IgA through glutamine supplementation during and after intense exercise. Eleven athletes performed cycle ergometer exercise for 2 h at 75% of maximal oxygen uptake on 3 separate days. Glutamine (a total of 17.5 g), protein (a total of 68.5 g/6.2 g protein-bound glutamine), and placebo supplements were given during and up to 2 h after exercise. Unstimulated, timed saliva samples were obtained before exercise and 20 min, 140 min, 4 h, and 22 h postexercise. The exercise protocol induced a decrease in salivary IgA (IgA concentration, IgA output, and IgA relative to total protein). The plasma concentration of glutamine was decreased by 15% 2 h postexercise in the placebo group, whereas this decline was abolished by both glutamine and protein supplements.None of the supplements, however, was able to abolish the decline in salivary IgA. This study does not support that postexercise decrease in salivary IgA is related to plasma glutamine concentrations.

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Effect of carb intake on plasma glutamine

Int J Sport Nutr 1998 Mar;8(1):49-59 Related Articles, Links


Effect of low- and high-carbohydrate diets on the plasma glutamine and circulating leukocyte responses to exercise.

Gleeson M, Blannin AK, Walsh NP, Bishop NC, Clark AM.

School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, England.

We examined the effects of a low-carbohydrate (CHO) diet on the plasma glutamine and circulating leukocyte responses to prolonged strenuous exercise. Twelve untrained male subjects cycled for 60 min at 70% of maximal oxygen uptake on two separate occasions, 3 days apart. All subjects performed the first exercise task after a normal diet; they completed the second exercise task after 3 days on either a high-CHO diet (75 +/- 8% CHO, n = 6) or a low-CHO diet (7 +/- 4% CHO, n = 6). The low-CHO diet was associated with a larger rise in plasma cortisol during exercise, a greater fall in the plasma glutamine concentration during recovery, and a larger neutrophilia during the postexercise period. Exercise on the high-CHO diet did not affect levels of plasma glutamine and circulating leukocytes. We conclude that CHO availability can influence the plasma glutamine and circulating leukocyte responses during recovery from intense prolonged exercise.

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Clin Nutr 2002 Oct;21(5):423-9 Related Articles, Links


Carbohydrate supplementation during intense exercise and the immune response of cyclists.

Bacurau RF, Bassit RA, Sawada L, Navarro F, Martins E Jr, Costa Rosa LF.

Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.

OBJECTIVE: To evaluate the effect of carbohydrate supplementation upon some aspects of the immune function in athletes during intense indoor cycling. METHODS: Twelve male athletes cycled for 20 min at a velocity corresponding to 90% of that obtained at the anaerobic threshold and rested for 20 min. This protocol was repeated six times. The athletes received, during the trial, water ad libitum, or a solution of carbohydrate (95% glucose polymers and 5% fructose) at 10% (w/v), 1 g kg h every 20 min, starting at the 10th minute of the first exercise period, plus extra water ad libitum. RESULTS: Exercise induced a reduction in peripheral blood mononuclear cell proliferation (37%) as well as in the production of cytokines by cultured cells (interleukin-1 (IL-1), interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), by 37%, 35%, 26% and 16%, respectively). All of these changes were prevented by the ingestion of a carbohydrate drink by the athletes, except that in IFN-gamma production, which was equally decreased (17%) after the second trial. The concentration of plasma glutamine, an important fuel for immune cells, was decreased in the placebo group but maintained in the group that received carbohydrate. CONCLUSION: Carbohydrate supplementation affects positively the immune response of cyclists by avoiding or minimizing changes in plasma glutamine concentration

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J Strength Cond Res 2002 Feb;16(1):157-60
The effects of high-dose glutamine ingestion on weightlifting performance

Antonio J, Sanders MS, Kalman D, Woodgate D, Street C.

Sports Science Laboratory, University of Delaware, Newark, Delaware 19716, USA.

The purpose of this study was to determine if high-dose glutamine ingestion affected weightlifting performance. In a double-blind, placebo-controlled, crossover study, 6 resistance-trained men (mean +/- SE: age, 21.5 +/- 0.3 years; weight, 76.5 +/- 2.8 kg(-1)) performed weightlifting exercises after the ingestion of glutamine or glycine (0.3 g x kg(-1)) mixed with calorie-free fruit juice or placebo (calorie-free fruit juice only). Each subject underwent each of the 3 treatments in a randomized order. One hour after ingestion, subjects performed 4 total sets of exercise to momentary muscular failure (2 sets of leg presses at 200% of body weight, 2 sets of bench presses at 100% of body weight). There were no differences in the average number of maximal repetitions performed in the leg press or bench press exercises among the 3 groups. These data indicate that the short-term ingestion of glutamine does not enhance weightlifting performance in resistance-trained men.